/*
 *  Copyright 2008-2010 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */


/*! \file math.h
 *  \brief Math-related metaprogramming functionality.
 */


#pragma once

namespace thrust {

namespace detail {

namespace mpl {

namespace math {

namespace detail {

// compute the log base-2 of an integer at compile time
template <unsigned int N, unsigned int Cur>
struct log2 {
    static const unsigned int value = log2 < (N >> 1), Cur + 1 >::value;
};

template <unsigned int Cur>
struct log2<1, Cur> {
    static const unsigned int value = Cur;
};

template <unsigned int Cur>
struct log2<0, Cur> {
    // undefined
};

} // end namespace detail


template <unsigned int N>
struct log2 {
    static const unsigned int value = detail::log2<N, 0>::value;
};


template <typename T, T lhs, T rhs>
struct min {
    static const T value = (lhs < rhs) ? lhs : rhs;
};


template <typename T, T lhs, T rhs>
struct max {
    static const T value = (!(lhs < rhs)) ? lhs : rhs;
};


template<typename result_type, result_type x, result_type y>
struct mul {
    static const result_type value = x* y;
};


template<typename result_type, result_type x, result_type y>
struct mod {
    static const result_type value = x % y;
};


template<typename result_type, result_type x, result_type y>
struct div {
    static const result_type value = x / y;
};


template<typename result_type, result_type x, result_type y>
struct geq {
    static const bool value = x >= y;
};


template<typename result_type, result_type x, result_type y>
struct lt {
    static const bool value = x < y;
};


template<typename result_type, result_type x, result_type y>
struct gt {
    static const bool value = x > y;
};


template<bool x, bool y>
struct or_ {
    static const bool value = (x || y);
};


template<typename result_type, result_type x, result_type y>
struct bit_and {
    static const result_type value = x& y;
};


template<typename result_type, result_type x, result_type y>
struct plus {
    static const result_type value = x + y;
};


template<typename result_type, result_type x, result_type y>
struct minus {
    static const result_type value = x - y;
};


template<typename result_type, result_type x, result_type y>
struct equal {
    static const bool value = x == y;
};


template<typename result_type, result_type x>
struct is_odd {
    static const bool value = x & 1;
};


} // end namespace math

} // end namespace mpl

} // end namespace detail

} // end namespace thrust

